Answer:
a. light from the sun reflects off the moon as it orbits earth.
Explanation:
Moon does not have its own light, it reflects the sunlight falling on it. Phases of moon are the different shapes of the moon that we see. There are mainly 5 phases of moon: New moon, Crescent, Half moon, gibbous and full moon. These shapes are due to the illuminated portion of the moon (by the Sun) that is visible from the Earth.
Thus, option a is correct.